Add memory usage metric

[evgenyfedorov2]

Fixes #6587

Microsoft Reviewers: Open in CodeFlow

Adding container.memory.usage metric with ObservableUpDownCounter instrument type, measured in bytes.

[Copilot]

Pull Request Overview

Adds a new container.memory.usage metric (bytes) as an ObservableUpDownCounter across Windows and Linux, updates logging, and extends tests to validate the new instrument.

• Introduce ContainerMemoryUsage constant and register it in both Windows and Linux providers.
• Refactor snapshot providers to expose container memory usage and separate percentage calculations, updating log messages.
• Extend unit and acceptance tests to subscribe to and assert on the new memory‐usage metric.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/.../Windows/WindowsContainerSnapshotProviderTests.cs	Added tests for combined container/process memory metrics and standalone usage test
test/.../Linux/LinuxUtilizationProviderTests.cs	Captured ContainerMemoryUsage in measurements, updated expected sample/retry counts
test/.../Linux/AcceptanceTest.cs	Subscribed to and asserted on new container memory usage gauge
test/.../ResourceUtilizationHealthChecks/ResourceHealthCheckExtensionsTests.cs	Added GetCurrentProcessMemoryUsage setup for health‐check tests
src/Shared/Instruments/ResourceUtilizationInstruments.cs	Added public const string ContainerMemoryUsage constant with XML docs
src/Libraries/.../Windows/WindowsSnapshotProvider.cs	Refactored memory methods, added _processMemoryLocker, new up/down counter, log rename
src/Libraries/.../Windows/Log.cs	Added ContainerMemoryUsageData and ProcessMemoryPercentageData messages
src/Libraries/.../Linux/Log.cs	Renamed MemoryUsageData to MemoryPercentageData, added new MemoryUsageData
src/Libraries/.../Linux/LinuxUtilizationProvider.cs	Refactored memory methods, added up/down counter for usage, updated retry helper

Comments suppressed due to low confidence (2)

src/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring/Windows/WindowsContainerSnapshotProvider.cs:234

• Logging while holding the _memoryLocker can lead to lock contention or unexpected delays. It’s safer to capture the values inside the lock and invoke the logger after releasing the lock to minimize the duration of the critical section.

                _logger.ProcessMemoryPercentageData(processMemoryUsage, _memoryLimit, _processMemoryPercentage);

src/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring/Windows/Log.cs:69

• The totalMemory parameter represents a byte count but is typed as double. For consistency with processMemoryUsage and to avoid implicit conversions, consider changing totalMemory to ulong.

        double memoryPercentage);